Holistic approach versus scientific evidence, what do we know about anti-aging herbal medicine in aging-associated neurodegenerative diseases?

In Asian countries such as China, Japan and Korea, some herbs are considered to be anti-aging herbs. According to the traditional medicine descriptions, these herbs have beneficial effects on aging-associated diseases and they intervene disease progression through a holistic approach. For a long time, this "holistic approach" statement remains difficult to be interpreted and is considered to be lack of scientific-evidence support. L. barbarum is a commonly used herb in China for both disease treatment and as functional food. It is also famous for its anti-aging properties. In this review, we use L. barbarum as an example to explain the "holistic approach" concept of anti-aging herbs. We discussed its effects on aging-associated neurodegenerative diseases such as glaucoma and Alzheimer's disease (AD). We proposed that the holistic properties of L. barbarum can be reflected in the following areas. Firstly, L. barbarum is a common food ingredient in Eastern countries. Carotenoid and polysaccharides components of L. barbarum are beneficial to the eye and therefore explained why it can be used as food therapy. Secondly, L. barbarum utilize multiple protective mechanisms to protect neurons against pathological damages. L. barbarum can directly modulate a number of intracellular signaling pathways and increase the expression of survival factors to enhance neuronal survival and attenuate apoptosis. On the other hand, L. barbarum indirectly regulate neuronal survival through modulating the activities of the surrounding microglia. Furthermore, L. barbarum provides beneficial effects on a number of aging-associated conditions, which can be risk factors of neurodegenerative diseases. These holistic actions for therapy and prevention may explain why L. barbarum is regarded as an anti-aging herb.